The objectives of my research are (1) to test the action of antimicrobial compound(s) of Pseudomonas fluroescens in preventing growth of mycotoxin producing fungi, and (2) to investigate the use of this plant beneficial bacterium as a biocontrol agent. Control of the growth of toxin producing fungi by antifungal compound(s) will be achieved by isolation of compound(s) from bacterial growth medium. Preliminary purification of antifungal compound(s) will be by high performance liquid chromatography (reverse phase chromatography) in different solvent systems. Once a homogeneous compound(s) is obtained, final identification will be performed by gas chromatography-mass spectroscopy, FT-infrared spectroscopy, and nuclear magnetic resonance. Mammalian toxicity of compound(s) will be determined in mice prior to field tests. The second phase of the project is to control fungal phytopathogens, which are of considerable economic importance. This will involve the isolation of gene(s) of antifungal compound(s) by transposon mutagenesis, cloning the 5' flanking sequence of mutated genes (antifungal mutant), and probing a genomic library of Pseudomonas or by direct complementation of an antifungal mutant, followed by genetic manipulation to optimize the production of compound(s) in vivo. The results of these studies should lead to specific control of fungi (in the field and in grain storage) that reduce the quality and quantity of yield and that are responsible for the production of mycotoxins, which are health hazards to humans and animals.